Shock strut



June 17, 1941.

w. H. MILLER snocx STRUT Filed Dec. 12, 19:56

vide'd to prevent relative members.

In aircraft landing gears, independent ind ierably; comprising cylinders.

Patented Junsi'l, i941 UNITED sures IPA'viIEN-T I isntxnr:srrull'lf I I I wimm'n. Miller, Philadelphia, Pa, assignor, by

meme assignmen to. to Bendix Aviation Corporatlon, South Bend, Ind-. corporation of.

Application December 12,1936, Serial him 115,597

- 110mm. (cres -s4) Q I I scopic tubular'members; wherein-means are prorotation between the vidual suspension of each landing wheel is employed to a consider-a le extent; the fuselage and 'This invention relates to "shock struts, and more particularly to shock struts employing telethe limits of the invention, reference being h'ad for purpose to the appended claim. I In the drawing. wherein similar reference characters refer to similar parts throughout the several views: I

Fig.1 is illustrative of a side view of theshock strut in its extended position, thesame being individual wheels bein connected by a strut pref-- e tubular members having some arrangement to absorb shock. In such an arrangement. one of the telescopic members may be rigidly secured and braced to the fuselage, and the other carry the whml, but in order to trt torsional stresses occurrin at the wheel due to ground irreitles, b, v

etc,- torsional str from one member to the other.

It is a feature or object of the present invention to provide a structure wherein relative rotamust be provided tor transmitting tion between telescopic members is prevented without interfering with the relative reciproca- A tory shock other object of the invention is to provide, in a shcckstrut of w t, spline means for preventing relative rotation between the members.

A further object of the invention is to provide,- in a shock strut of the telescopic tubular type, spline means for preventing relative rotation beclosed within the members. i I

Still another object of the invention is to provide, in a shock strut oi the telescopic tubular type, spline in between the members protected from exposure and immersed in the shock absorbing liquid within the strut members, for

lubrication. I

'Yet another object of the invention is to provide, in a shock strut, splines evenly distributed around the interengaging surfaces of the members, the splines being exposed to the shock ab- I sorbing liquidus'ed in the strut to provide free lubricated axial movement and a broad proarbing ovement between the tween the members, the spline means being enend 40 lying adjacent the orifice when the strut I isextended, and the base "approaching the teoted bearing surface against relative rotation between the members.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawing. It is expressly understoodyhoweve'r. that the drawing is employed for purposes of illustration only and is not designed as a definition of shown witha quarter section removed;

Fig. 2 is a front view of the strut as mounted in practice with attachment braces;

, Fig. 3 is a side view of the lower portion of I r the strut as shown in Fig. 2; and

Fig. 4 is a broken cross-section through the -strut taken on the line M, of Fig. 1.

Referring to the drawing, and particularly/Fig.

1, there will be seen telescopic casings i0 and it, I

the upper casing iii being outside of the lower casing' it, and being adapted for securing to an aircraft fuselageby any suitablemeans such as the eye It in the end cap it. The upper casing, as shown is divided in .two sections 58 and 20, secured together by a sleeve 22 having a diaphragm 25 centrally located therein with a central orifice 28, the purpose of which will be described hereincooperate with the hereinbefore described diaphragm and orifice 26. The metering pin may obviously be of any preferred shape and may, if a uniform orifice is desired, be dispensed with. The pin shown is tapered in form, the small orifice when the strut is compressed.

To support the load of the plane while taxiing,

a spring is also carried onthe head cap 34.

and is adapted to engage the under side of the diaphragm 24 when the strut has been compressed to a certain degree by'the initial shock f of landing.

The outer casing at its lower end is provided with an outside sleeve 46 extending below the end thereof to provide a space for packing material II I 48, the latter being positioned between an L shaped ring 50 seated against the end of member or r' e-j-a l0, and a packing nut 52 threaded into the sleeve 48. Ihe nut ll and the smooth exterior surface on the lower end of the inner member l2, and

the head can 34 and the smooth interior surface 2,c4s,ooo 4 v I packing II. In the event that this space becomes full of liquid. on the expansion stroke, the liquid ings, and transmit torsional stresses from the lower inner casing I! to the upper outer casing ill, the inner casing i2 is provided with short ex-' ternal splines 56 engaging with interior splines 58 in the lower portion of the outer casing Ill. The upper end 60 of the splines 58 may act as a limiting means governing maximum extension of the strut by engaging with the shoulder formed by the under edge 02 of the head cap 34.

in practice the strut is filled with oil or other liquid through filler plug 64 to a level which may be determined by removal of plug 66 and filling until bleeding takes place, this level being determined with the strut extended and not loaded. During the compression stroke, as while landing,

air may be entrapped in the top space 68 or a practice leakage of shock absorbing liquid past the cup washer I0 into the interrupted annular space 12 afl'ords lubrication to the splines, since the liquid generally contains considerable oil. Es-

cape beyond the splines is prevented by the may flow upward past the cup washer into the spring chamber.

There is thus provided a strut having reciprocating members splined against rotation in a manner such as to reduce friction and wear to a minimum, the splines being protected from the elements of weather, and being subjected to lubrication by the liquid within the strut.

Though a single embodiment of the inventionv has been illustrated and described, it is to be understood that the, invention is not limited thereto but may be embodied in various alternative forms. As many changes in construction and arrangement of parts may be made without departing from the spirit of the invention as would be apparent to those skilled in the art, reference will be had to the appended claim for a definition of the limits of the invention.

What is claimed is: I

A shock strut comprising an outer member, raised internal splines on a portion of the inner surface of said outermember, a telescoping inner member, external splines on the internal member, matching and interengaging the internal splines of the outer member, and an unsplined portion on said inner member having an axial size substantially the same as the outer surfaces of the external splines, adapted to act as a bearing surface for the unsplined portion on the outer memher, and to act as astop to relative movement between the two members.

' WILLIAM H. MEIER. 

